8:31 p.m.
I was going to +1 - I like Kito's idea of using a component
author-specified attribute, and I also like Dan's idea of a more generic
"strict" attribute - though then it occurred to me that the arbitrary
attribute behavior isn't just a feature of Facelets compositions - but
this is also the way that Facelets works for any old (Java-based) Faces
component. That is, I believe that:
<h:commandButton foo="bar">
Just ends up stashing the "foo" attribute value in the
<h:commandButton>'s attribute map. (Or, at least, I think that's what
happens.) So now I am wondering whether there is merit in keeping
behavior consistent between composite and non-composite components in
this regard. Would it be confusing that arbitrary attributes are pushed
into the attribute map for some types of components, but not for
others? Hmm... maybe the benefits of providing quick feedback in cases
where the attribute is known to be invalid (ie. in the composite
component "strict" case) outweigh the drawbacks of the inconsistency?
If we do go forward with a strict capability for composite components,
do we want to check/enforce this in all project stages? Seems like we
might be able to get away with only performing the strict checks in the
development project stage (sort of like disabling assertions for
production releases).
Andy
Dan Allen wrote On 4/2/2009 2:34 PM ET:
Makes sense to me. One of the things I have always been uneasy about
with Facelets is the amorphous aspect of the tags. So when it comes to
defining a real component, I think we absolutely want the component
author to be able to decide whether to make the tag strict or not.
Would a more generic attribute like strict="true" make more sense just
in case we want to enforce other restrictions?
-Dan
On Thu, Apr 2, 2009 at 7:56 AM, Kito Mann <kito.mann(a)virtua.com
<mailto:kito.mann@virtua.com>> wrote:
So, here's one other thing that came up at JSFDays -- the fact
that composite components (like Facelet compositions) don't
restrict which attributes can be used. This is fine for Facelet
compositions, but since composite components can define specific
attributes, it makes sense to give component authors the ability
to restrict page authors to those attributes.
I think the easiest way to handle this from a component author's
perspective would be to add an attribute to the
<component:interface> tag:
<component:interface restrictAttributes="true">
<component:attribute name="name" required="true"/>
<component:attribute name="size"/>
</component:interface>
So, in this case, this component would _only_ accept the name and
size attributes, and the runtime would throw an exception if
another attribute were used. An IDE could also complain when
someone tried to use a different attribute.
Thoughts?
---
Kito D. Mann -- Author, JavaServer Faces in Action
http://twitter.com/kito99 http://twitter.com/jsfcentral
http://www.virtua.com - JSF/Java EE consulting, training, and
mentoring
http://www.JSFCentral.com - JavaServer Faces FAQ, news, and info
+1 203-404-4848 x3
Public JSF Course in NYC (April 21st-24th):
http://www.regonline.com/jsf-course
--
Dan Allen
Senior Software Engineer, Red Hat | Author of Seam in Action
http://mojavelinux.com
http://mojavelinux.com/seaminaction
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